1. Field of the Invention
The present invention relates to a method and apparatus for searching an image, and more particularly, to an apparatus for searching a digital image using characteristics such as the color and texture of the digital image.
2. Description of the Related Art
In general, in conventional image search methods, searching is performed using characteristics such as the color and the texture of an image. Such searching methods are widely used in image search engines. Also, in many cases, the color and the texture of the entire image are used in such search methods. However, in the conventional search methods, the probability of successfully detecting a desired image becomes lower when the size of the image is large and various kinds of objects are included as, for example, in an aerial photograph. Also, since the conventional method extracts the characteristic of an entire image, it takes an excessively long processing time in the case where the image is large in size and the contents thereof are complicate Accordingly, the conventional searching procedure is inefficient.
To solve the above problem, it is an object of the present invention to provide a digital image searching apparatus for performing a region-based search.
It is another object of the present invention to provide a digital image searching method that utilizes a region-based search.
Accordingly, to achieve the foregoing objects, there is provided a digital image search apparatus, comprising a database processing unit for (1) segmenting an image from the database or an image which is not stored in the database into homogeneous regions, (2) analyzing the segmented regions and (3) storing the segmented regions, and an image search engine unit for searching for an image having a segmented region showing a characteristic similar to the characteristic of a query region.
The image search engine unit preferably searches for a plurality of images having a segmented region showing a characteristic similar to the characteristic of the query region and searches for a region having a position similar to the absolute position or a relative position of the query region in a query image.
The characteristic of the region is preferably one selected from a characteristic group consisting of a color histogram showing the characteristics of colors, Gabor wavelet coefficients showing characteristics of texture, a boundary description showing the characteristic of shape, and a relative and absolute position of the region from anywhere within an entire image or a combination of a plurality of characteristics. Such characteristics may include a color histogram showing the characteristics of colors, Gabor wavelet coefficients showing the characteristics of texture, a boundary description showing the characteristic of shape, and a relative and absolute position from anywhere within an entire image.
To achieve the foregoing objects, there is provided an alternative digital image search apparatus, comprising a database processing unit and an image search engine. The data processing unit comprises region segmentation portion that receives an image and segments the image into homogeneous regions, a region characteristic analyzing portion that analyzes the characteristic of the segmented regions, and an image and region characteristic store for storing the characteristic of each image and region. The image search engine comprises an inputting unit for receiving a query image from a user interface, determining whether the query image is in the database, and outputting the image. The image search engine also includes a selecting unit for outputting the segmented region and the characteristic, the selecting unit being connected to a user interface and receiving a query region and a characteristic, selected by the user. The image search engine further includes a searching unit for searching an image having a segmented region showing a characteristic similar to the characteristic of a query region in the query image and region characteristic store, and outputting searched image information. Finally, the image search engine includes an outputting unit for outputting searched images, where the searched image is the image in a database corresponding to the information of the searched image which is input from the searching unit.
To achieve the foregoing objects, there is provided a digital image search method, comprising a database processing step for segmenting an image from database or a search image which is not stored in the database and analyzing and storing the characteristic of the segmented regions and an image searching step for searching for an image having a segmented region showing a characteristic similar to the characteristic of the segmented region. The database processing step comprises the steps of receiving a database image, segmenting the received image into homogeneous regions, analyzing the characteristic of the segmented regions, and storing the characteristic for each image and region. The image searching step comprises the steps of receiving a search image, determining whether the received image is in the database, restoring characteristic data in each region when it is determined whether the received image is in the database in the determining step, segmenting the input image into homogeneous regions when it is determined that an input image is not in the database in the determining step and analyzing and storing the characteristic of the segmented regions, selecting a query region of a query image and a characteristic to be searched, and searching for an image in the database including a region having a characteristic similar to that of the query region.